Cationic catalyst system

ABSTRACT

A 3+ metal complex for coordination polymerization of olefins is disclosed. The precursor metal complex is stabilized by a anionic multidentate ligand and at least two monoanionic ligands. The multidentate ligand and the transition metal form a metallocycle having at least five primary atoms, counting any π-bound cyclopentadienyl group in the metallocycle as two primary atoms. Olefin polymerization is exemplified.

FIELD

This invention relates to certain transition metal compounds containinga neutral polyhaptate ligand and a tethered or bulky anionic ligand withthe transition metal preferably in the +3-oxidation state, and to acatalyst system comprising those compounds and optionally alumoxane,modified alumoxane, or non-coordinating anion activator, Lewis acid, orthe like to form active catalyst species, preferably cationic, for theproduction of polyolefins such as polyethylene, polypropylene andalpha-olefin copolymers of ethylene and propylene having a highmolecular weight.

BACKGROUND

It is well known to those skilled in the art that the polyhaptate natureof the cyclopentadienyl anion confers unique properties topolymerization catalysts derived therefrom such as stability towardligand loss or exchange and occupation of several coordination sites onthe metal center (e.g. three in the pseudo octahedral environment ofCpCr(CO)₃) so that its coordination environment is controlled and welldefined. This results in more single sited behavior of the catalystsystems relative to e.g. Ziegler-Natta TiCl₄/aluminum alkyl basedsystems, conferring all the benefits of single sited nature such asnarrow distributions of molecular weight and comonomer and “tunability”of catalyst performance by variations in the polyhaptate ligand. For thepurposes of the description of the invention in this section,“polyhaptate” is taken to mean a ligand that contacts a metal center ina bonding interaction through more than one atom, whether thepolyhaptate ligand has a formal charge or is neutral. Thus the “neutralpolyhaptate ligand” will contact the transition metal through at leasttwo atoms which are not considered to have a localized, negative chargeor a negative charge delocalized between them as in cyclopentadienide.Similarly, the “tethered or bulky monoanionic ligand” may be polyhaptateand will have a negative charge. It is further well known that additionof a second cyclopentadienyl ligand or a tethered anionic ligand to formbiscyclopentadienyl complexes or e.g. dimethylsilylbridgedcyclopentadienylamide (so called “constrained geometry”) complexesresults in improved performance relative to the more open, lesssterically locked complexes such as CpZrCl₃, CpZr(OR)₃, or CpTiCl₃ andthe like which generally show broader comonomer and molecular weightdistributions associated with a multi-sited nature as well as loweractivity. Thus the favored “well defined ligand sets” contain apolyhaptate ligand with a bridged monohaptate ligand or an optionallybridged second polyhaptate ligand. Generally in the art the preferred“well defined” catalysts systems use: polyhaptate dianionic ligand setssuch as biscyclopentadienyl or bridged cyclopentadienylamido; they useGroup 4 metals, especially Zr and Ti; the metals are in their highestoxidation state and are accepted to be cationic with one alkyl orpolymer ligand for chain propagation and one open coordination site forolefin coordination prior to or concurrent with insertion; there are noother labile ligands e.g. chloride, alkoxide, carboxylate left on themetal; and a weakly or “non” coordinating anion balances charge. Somenickel-based systems recently reported both by Johnson at DuPont andGrubbs at Caltech are believed effective in the neutral form. In orderto maintain the favorable coordination environment of the polyhaptatedianionic ligand sets while using transition metals other than Group 4,many have substituted one or both anionic cyclopentadienyl (Cp) or amidoligands with isoelectronic dianionic analogues. Thus Bazan'ssubstitution of one Cp with a dianionic borrole (C₄H₄BR²⁻) allowssynthesis of Group 5 complexes in their highest oxidation state whilepreserving as many of the characteristics of the preferred “well definedligand set” systems as possible. Similarly Gibson's substitution of twoCps with dianionic imido ligands yields chromium catalysts in theirhighest oxidation state. This strategy only allows the preparation ofcationic catalysts from Groups 5 or higher, while neutral versions couldbe made for Group 4 or higher. Much less common has been the strategy tomaintain one polyhaptate anionic ligand such as Cp and use a tetheredneutral ligand to create the “well defined” ligand set. This approachallows the preparation of Group 3 analogues and catalysts from any groupin the 3+ oxidation state or lower.

We are not aware of anyone using the approach of substituting thepolyhaptate anionic ligand such as Cp with a polyhaptate neutral ligandand an anionic ligand, both selected to provide a “well defined” i.e.relatively non labile ligand set. This has the advantage of allowing avalence to offset the anionic propagating polymer chain and a valence tocreate a positive charge with an open coordination site if desired. Manypolyhaptate ligands offer far more structural diversity and ease ofsynthesis than e.g. substituted Cps, e.g. hexahydrotriazines made fromthe condensation of formaldehyde with amines. This could allow the useof any transition metal with a readily accessible 3+ oxidation statesuch as Sc, Y, La, lanthamides and actinides, V, Nb, Cr, Co, etc. It isthis concept that is embodied in the present invention. It is notanticipated that the active species must be cationic or must be in a 3+oxidation state because those skilled in the art will know that neutralcomplexes or lower oxidation states may prove competent for catalysts,or that the exact nature of the active species may be difficult to provewhen it is derived e.g. from a lower oxidation state starting material.Rather, the catalysts of the invention will be distinguished in thatthey contain at least a neutral polyhaptate ligand and an anionicligand, for which said anionic ligand will be either bridged to thepolyhaptate ligand or be of a size to afford some degree of stericprotection against its substitution.

Neutral scandium compounds having two univalent ligands or a bidentate,divalent ligand are known from Shapiro et al., Organometallics, vol. 9,pp. 867–869 (1990); Piers et al., J. Am. Chem. Soc., vol. 112, pp.9406–9407 (1990); Shapiro et al., J. Am. Chem. Soc., vol. 116, pp.4623–4640 (1994); Hajela et al., Organometallics, vol. 13, pp. 1147–1154(1994); and U.S. Pat. No. 5,563,219 to Yasuda et al. Similar yttrium,lanthanum and cerium complexes are disclosed in Booij et al., Journal ofOrganometallic Chemistry, vol. 364, pp. 79–86 (1989) and Coughlin etal., J. Am. Chem. Soc., vol. 114, pp. 7606–7607 (1992). Polymerizationwith a metal scandium complex having a bidentate, divalent ligand usinga non-ionizing cocatalyst is known from U.S. Pat. No. 5,464,906 toPatton et al.

Group-3-10 metallocyclic catalyst complexes are described in U.S. Pat.Nos. 5,312,881 and 5,455,317, both to Marks et al.; U.S. Pat. No.5,064,802 to Stevens et al.; and EP 0 765 888 A2.

Polymerization of olefins with cationic Group-4 metal complexes isillustrated in WO 96/13529 and WO 97/42228. Boratabenzene complexes ofGroup-3-5 metals are disclosed in WO 97/23493.

Amidinato complexes of Group-3-6 metals are disclosed in U.S. Pat. No.5,707,913 to Schlund et al. Group 4 bisamido catalysts are disclosed inU.S. Pat. No. 5,318,935 to Canich, et al., and related multidentatebisarylamido catalysts are disclosed by D. H. McConville, et al,Macromolecules 1996, 29, 5241–5243.

Monoanionic and Polyhaptate Ligands for Catalysis.

While replacing Cp⁻ ligands with dianionic formal 6 electron donors hasbeen known to give active catalysts if the metal identity or number oflabile ligands are adjusted to maintain an “isoelectronic” state, thepractice of using 6 electron neutral donor ligands has received littleattention. We believe that the ligand set defined by a neutralpolyhaptate donor optionally bridged to a monoanionic donor are suitedto stabilize lanthamides, actinides, and group 3 metals, Ti^(III),V^(III), Cr^(III), Fe^(III), and Co^(III) in configurations with twolabile ligands such as chloride in such a way as to promotepolymerization activity with a suitable activator. It is depicted asfollows:(L)T(E)MQ_(x)L′_(y)(where T=optional bridge, L=polyhaptate neutral donor ligand,E=monoanionic ligand, M=a metal, preferably in the 3+ oxidation state,Q=labile ligands such as chloride, methyl, etc., L′=neutral donorligands such as ethers, phosphines, amines, LiCl, olefins,cyclooctadiene). Versions with a single Q ligand for Fe^(ll) etc. couldreadily be envisioned.

SUMMARY

The present invention is directed to a catalyst system for olefinpolymerization. The catalyst system contains a formally +3 cationicmetal center stabilized by a neutral 6-electron donor and a monoanionicdonor optionally bridged to the multidentate neutral ligand. The metalcan be any +3 actinide, lanthamide, or Group-3, -4, -5, -6, -7, -8, -9transition metal, or +3 main group metal.

In one embodiment, the multidentate ligand, A, has the formula LTEwherein L is a bulky neutral π-donating ligand, preferably containing atleast two Group-15-16 atoms, most preferably at least three. T is acovalent bridging group containing a Group-13, -14, or -15 element. E isan anionic ligand containing a Group-14-16 element, includingπt-donating hydrocarbyl and heterohydrocarbyl ligands, substituted amidoor phosphido ligands, oxygen or sulfur, or other ligands or atomscovalently bound to T. Alternatively, E is JR′_(z) where J represents anelement from Group-15 or -16. When J is a Group-15 element, z=2, andwhen J is a Group-16 element, z=1. Finally, each R′ is independentlyselected from suitable organic ligands as defined below.

In a further embodiment, a polymerization process according to thepresent invention (invention polymerization process), such as thepolymerization or copolymerization of olefins, comprises the steps ofactivating (ionizing) the +3 metal component to a cation (the catalyst)and contacting it with suitable feedstocks. These feedstocks containpredominately one monomer for homopolymerization; they contain monomermixtures for copolymerization. Suitable feedstocks are made up of anydesired mixture of ethylene, C₃–C₂₀ α-olefins, C₅–C₂₀ diolefins,acetylenically unsaturated monomers, or other unsaturated monomers. Thecatalyst can optionally be dissolved, suspended, or fluidized in asuitable liquid or gaseous polymerization diluent. The catalyst isactivated with alumoxanes, modified alumoxanes, non-coordinating anionactivators, Lewis acids or the like, (alone or in combination), with analuminum-to-non-coordinating-anion or Lewis-acid-to-transition-metalmolar ratio of about 1:10 to about 20,000:1 or more. The catalyst reactswith the monomer(s) from about −100° C. to about 300° C. for about onesecond to about 10 hours to produce a polyolefin having from about 1000or less to about 5,000,000 or more weight average molecular weight andfrom about 1.5 to about 15 or greater molecular weight distribution.

In another further embodiment, the monoanionic ligand is a substitutedphenol joined through an all-carbon bridge to a 6-electron neutral donorligand. Thus, H₂C(Me₂tacn)(^(t)Bu₂C₆H₂O)ScCl₂ (1, Me₂tacn=dimethyltriazacyclononane, see figure below) polymerizes ethylene when treatedwith MAO.

Neutral group three metallocenes (^(R)CP₂MX) tend to dimerize andgenerally show lower activities than cationic group 4 analogues (e.g.Cp₂ZrMe⁺NCA⁻, NCA=counter anion). Substituting a neutral ligand such asMe₃tacn for Cp would allow the stabilization of isoelectronic groupthree cationic species (e.g. Cp(Me₃tacn)jYMe⁺NCA⁻) which should be lessinclined to dimerize and thus should show more activity. Polyhaptatestructures with “hard” donor ligands will be preferred as they may beexpected to bind more tightly and be less inclined to be removed byLewis acids such as trialkyl aluminum scavengers, methylalumoxanes, andB(C₆F₅)₃.

The mono-anionic donor ligand E need not be bridged to the neutral donorligand, nor must it be monohaptate. When it is not bridged to theneutral donor, preferred structures are those that contain steric bulkto help prevent the anionic donor from being removed similarly to thelabile ligands. Preferred examples are 2,6-^(i)Pr₂ArO—, amidinateligands, and disubstituted amides.

The neutral polyhaptate ligand L may contain donor “heteroatoms” fromgroups 15–17 of the periodic table, olefins, alkynes, or neutral carbenegroups. The neutral donor may be bidentate, tridentate, tetradentate, oreven higher denticity. The donor groups may be linked in a ring as withtacn (triazacyclononane) derivatives, in chains, to a central atom or ina combination thereof. Preferred structures are the triazacyclononanes(9-membered ring), and hexahydrotriazines (6-membered ring). It isexpected that different ring sizes will be optimal for different metalsand anionic donor ligands. Each linker between heteroatoms or neutralcarbon donors need not be of the same composition or length.

The usual ionizing activators known to those skilled in the art may beused for the invention or the compounds may be used without additionalactivation. Non-coordinating anions comprising perfluoroaryl borates andaluminates are preferred activators since they will not be able to bindthe neutral donor atoms of the polyhaptate ligand in a Lewis acid manneras might boranes and neutral aluminum alkyls.

It is clear now that a wide range of molecular weight capability,comonomer incorporation, tacticity control, shear thinning, meltstrength, film tear values, and a host of other properties arecontrolled by variations in catalyst structure and process conditions.To hope to achieve the desired balance of all properties using a givenprocess, a broad selection of catalysts behaviors is essential. It isexpected that the catalysts of the invention will provide further toolsto achieve these goals.

Definitions

Catalyst system encompasses a catalystprecursor/activator pair. Whencatalyst system is used to describe such a pair before activation, itmeans the unactivated catalyst together with the activator. Whencatalyst system is used to describe such a pair after activation, itmeans the activated catalyst and the NCA or other charge-balancingmoiety.

Cp or cyclopentadienyl encompasses all substituted and unsubstitutedligands in which the 5-carbon-atom, planar aromatic cyclopentadienideion can be found. This specifically includes fused ring systems in whichthe 5-carbon ring is fused with other 5-membered rings and fused with6-and-greater-membered rings. It also specifically includes ligands inwhich ring carbon atoms are substituted with heteroatoms givingheterocyclic systems. The cyclopentadienyl ligand's 5-member,substantially planar ring should be preserved (heterocyclic orhomocyclic), including the π-electrons used to coordinate, side on, toM. Some examples of Cp or cyclopentadienyl are fluorenyl, indenyl, andcyclopentadiene monoanion itself.

Feedstocks are any desired mixture of ethylene, C₃–C₂₀ α-olefins, C₄–C₂₀diolefins, acetylenically unsaturated monomers, or other unsaturatedmonomers. These feedstocks contain predominately one monomer forhomopolymerization; they contain monomer mixtures for copolymerizationreactions.

L′ is a neutral Lewis base such as, diethyl ether, tetrahydrofuran,dimethylaniline, trimethylphosphine, lithium chloride, or the like,coordinated to the metal-center. It also optionally binds to one or bothX, with an appropriate X. L′ can also be a second transition metal ofthe same type as the metal center giving a dimeric catalyst or catalystprecursor, if both of the transition metals are the same or a bimetalliccatalyst or catalyst precursor if the transition metals are different.

Monodentate means that a ligand is coordinated to an atom throughsubstantially one, substantially discrete, ligand-atom connection, whichis intended to be coextensive with the art recognized meaning.

Bidentate means that a ligand is coordinated to an atom throughsubstantially two, substantially discrete, ligand-atom connections. Thisdefinition of bidentate is intended to be coextensive with theart-recognized meaning.

Multidentate means that a ligand is substantially coordinated to an atomthrough more than one substantially discrete, ligand-atom connection,which is intended to be coextensive with the art recognized meaning.

Noncoordinating anion (NCA) is art recognized to mean an anion thateither does not coordinate to the metal cation or that does coordinateto the metal cation, but only weakly enough that a neutral Lewis base,such as an olefinically or acetylenically unsaturated monomer candisplace it. Any metal or metalloid that can form a compatible, weaklyor negligibly coordinating complex may be used or contained in thenoncoordinating anion. Suitable metals include, but are not limited to,aluminum, gold, and platinum. Suitable metalloids include, but are notlimited to, boron, phosphorus, and silicon. The description ofnoncoordinating anions and their precursors in the documents cited inthe paragraphs above are incorporated by reference for purposes of U.S.patent practice.

Polymerization encompasses any polymerization reaction such ashomopolymerization and copolymerization. It encompasses polymerproduction including both homopolymers and copolymers with otherα-olefin, α-olefinic diolefin, or non-conjugated diolefin monomers, forexample C₃–C₂₀ olefins, C₄–C₂₀ diolefins, C₄–C₂₀ cyclic olefins, orC₈–C₂₀ styrenic olefins. Other olefinically unsaturated monomers besidesthose specifically described above may be polymerized using theinvention catalysts, for example, styrene, alkyl-substituted styrene,ethylidene norbornene, norbornadiene, dicyclopentadiene,vinylcyclohexane, vinylcyclohexene, and other olefinically-unsaturatedmonomers, including other cyclic olefins, such as cyclopentene,norbornene, and alkyl-substituted norbornenes. Copolymerization can alsoincorporate α-olefinic macromonomers of up to 1000 or more mer units.

Q are abstractable ligands or leaving groups and olefin insertionligands connected to the metal center. Usually, activation occurs whenone or more Q are removed from the metal. Also, one or more Q remainsand as part of the polymerization process, olefin monomer inserts intothe metal-center-Q bond. Thus, the Q that remains on the metal center isknown as an olefin insertion ligand. Qs independently include, but arenot limited to, monoanionic ligands selected from, hydride, hydrocarbyl,alkoxide, aryloxide, amide, or phosphide radicals. Furthermore, both Qtogether may be an alkylidene, a cyclometallated hydrocarbyl, or anyother divalent anionic chelating ligand, or Q can be a diene. ExemplaryQ in the formulas are diethyl, propyl, butyl, pentyl, isopentyl, hexyl,isobutyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl, phenyl,benzyl, trimethylsilylmethyl, triethylsilylmethyl and the like, withtrimethylsilylmethyl being preferred. Exemplary halogen atoms for Qinclude chlorine, bromine, fluorine, and iodine, with chlorine beingpreferred. Exemplary alkoxides and aryloxides for Q are methoxide,phenoxide and substituted phenoxides such as 4-methyl-phenoxide.Exemplary amides for Q are dimethylamide, diethylamide,methylethylamide, di-t-butylamide, diisopropylamide, and the like.Exemplary arylamides are diphenylamide and any other substitutedphenylamides. Exemplary phosphides for Q are diphenylphosphide,dicyclohexylphosphide, diethylphosphide, dimethylphosphide, and thelike. Exemplary alkylidene radicals for both Q together are methylidene,ethylidene, and propylidene. Exemplary cyclometallated hydrocarbylradicals for both Q together are propylene, and isomers of butylene,pentylene, hexylene, and octylene. Exemplary dienes for both Q togetherare 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, 1,3-hexadiene,1,4-hexadiene, 1,5-hexadiene, 2,4-dimethyl-1,3-butadiene,2-methyl-1,3-pentadiene, 2-methyl-1,3-hexadiene, and 2,4-hexadiene. Qscan also be simple alkyl ligands substituted with at least one trialkylsilyl group. The most preferred Q is —CH₂SiMe₃.

R, R′, and R″ encompass:

-   -   (i) C₁–C₂₀ hydrocarbyl radicals;    -   (ii) C₁–C₂₀ substituted hydrocarbyl radicals in which a halogen        atom, amido, phosphido, alkoxy, or aryloxy group or any other        radical containing a Lewis acidic or basic functionality replace        one or more hydrogen atoms including straight and branched alkyl        radicals, cyclic hydrocarbon radicals, alkyl-substituted cyclic        hydrocarbon radicals, aromatic radicals, alkyl-substituted        aromatic radicals such as trifluoromethyl, dimethylaminomethyl,        diphenylphosphinomethyl, methoxymethyl, phenoxyethyl,        trimethylsilylmethyl and the like; and    -   (iii) C₁–C₂₀ hydrocarbyl-substituted metalloid radicals wherein        the metalloid is a Group-13-14 element such as trimethylsilyl,        triethylsilyl, ethyldimethylsilyl, methyldiethylsilyl,        triphenylgermyl and the like.

Additionally, any R or R″ may join with one or more R or R″ to form aring structure. Separately, R″ may also be a hydride radical.

TACN is 1,4,7-triazacyclononane.

TAN is 1,5,9-triazanonane.

TACH is 1,3,5-triazacyclohexane.

DACN is 1,4-diazacyclononane.

TACDD is 1,5,9-triazacyclododecane.

TNNCN is 1,2,6-triazacyclononane.

TNNCH is 1,2,5-triazacycloheptane.

TAH is 1,4,7-triazaheptane.

DETAILED DESCRIPTION

The transition metal complex of the catalyst system of the invention maybe represented by the formula:(L)T(E)MQ_(x)L′_(y)

M is a metal preferably in a +3 oxidation state.

L, optionally T, and E comprise the polyhaptate neutral donor ligand,optional bridge, and anionic ligand; Q (x=0–3) are independentlymonoanionic ligands selected from halide, hydride, hydrocarbyl,alkoxide, aryloxide, amide or phosphide radicals. For Q of 2 or more,two Q together may be an alkylidene or a cyclometallated hydrocarbyl orany other divalent anionic chelating ligand, or a diene, but may not bea substituted or unsubstituted cyclopentadienyl radical. L′ (y=0–3) aredonor ligands. It is anticipated that the number of Q may be such thatthe complex bears a negative charge (i.e. an “ate” complex such as(LTE)ScCl₃ ⁻Li⁺) and still be suitable for the inventive use.

L is a polyhaptate ligand and may contain donor “heteroatoms” fromgroups 15–17 of the periodic table, olefins, alkynes, B—N pi bonds, orneutral carbene groups such that the atoms bound to M do not containsubstantial negative charge. The neutral donor may be bidentate,tridentate, tetradentate, or even higher denticity. The donor groups maybe linked in a ring as with tacn (triazacyclononane) derivatives, inchains, to a central atom or in a combination thereof. Preferredstructures are the triazacyclononanes (9-membered ring), andhexahydrotriazines (6-membered ring). It is expected that different ringsizes will be optimal for different metals and anionic donor ligands.Each linker between heteroatoms or neutral carbon donors need not be ofthe same composition or length. L is capable of donating at least fourelectrons to M. Preferably L contains two, or more preferably three,Group-15 or -16 atoms. In a preferred embodiment, these atoms arenitrogen. A preferred geometry of L is such that it coordinates to themetal through the Group-15 atoms' lone pair electrons reminiscent of η⁵,cyclopentadienyl side-on coordination.

T is an optional covalent bridging group containing at least one Group13–16 atom. When present, it connects the multihaptate ligand, L, withthe anionic ligand, E, and completes a metallocycle fragment, M(LTE).T's chain length influences the geometry of the metallocycle fragment.Examples of T include, but are not limited to, dialkyl, alkylaryl ordiaryl, silicon or germanium radicals, alkyl or aryl, phosphine or amineradicals, or hydrocarbyl radicals such as methylene, ethylene, andisopropylene. In a preferred embodiment, the polyhaptate ligand joinedto the monoanionic ligand is a substituted phenol joined through an allcarbon bridge to the polyhaptate neutral group.

E is an anionic ligand containing at least one group 14–16 element andmay be a substituted or unsubstituted, cyclopentadienyl, allyl, or otherdelocalized pi-anion, a Group-15 ligand such as amide, phosphaimide, orphosphide, or Group-16 ligand such as aryloxide or thiolate.

Preferably when E is not bridged to L it will be branched on the atombound to M or on the next (beta) atom, or it will be part of apolyhaptate binding group or otherwise sterically protected againstsubstitution. Examples of E include N(SiMe₃)₂, diisopropylphenyl,—N═PR₃, and substituted amidinates.

When E is a substituted cyclopentadienyl ligand, the substitution canoccur on the ring, keeping the C₅ ring intact (on-ring substitution), orcan occur in the ring, creating heterocyclic compounds (in-ringsubstitution). On-ring substitutions range from simple unitarysubstitution up to the replacement of multiple hydrogen atoms withmultidentate ligands forming fused-ring systems such as in- or on-ringsubstituted, or unsubstituted, fluorenyl or indenyl ligands. Animportant characteristic of a cyclopentadienyl ligand is that the5-member, substantially planar ring be preserved (heterocyclic orhomocyclic), including the π-electrons used to coordinate, side on, toM.

Q are independently monoanionic ligands selected from halide, hydride,hydrocarbyl, alkoxide, aryloxide, bridging oxo or sulfide, amide orphosphide radicals. For Q of 2 or more, two Q together may be analkylidene or a cyclometallated hydrocarbyl or any other divalentanionic chelating ligand, ═NH, oxo or sulfido, or a diene, but may notbe a substituted or unsubstituted cyclopentadienyl radical.

L′ is a neutral Lewis base such as, diethyl ether, tetrahydrofuran,dimethylaniline, trimethylphosphine, lithium chloride, cylcooctene,cyclooctadiene or the like, and optionally covalently binds to one orboth X. L′ can also be a second transition metal of the same type, i.e.the transition metal component can be dimeric if both of the transitionmetals are the same or bimetallic if they are different.

In a preferred embodiment the transition metal complex of the catalystsystem of the invention is believed to be cationic and may berepresented by the formula:[(L)T(E)MQ_(x)L′_(y)]⁺[NCA]⁻

M is a metal preferably in a +3 oxidation state.

The compositions of L, T, E, M, Q, L′, x, and y are essentially the sameas in the neutral transition metal catalyst above, except that thepreferred Q will not be halide, alkoxide, or amide unless the catalystis used in the presence of a main group alkyl complex such as trialkylaluminums, alkyl zincs, methyalumoxane, trialkylboron, and the like. NCAis a weakly or non-coordinating anion that balances the positive chargeon the transition metal catalyst complex. Non-coordinating anionscomprising perfluoroaryl borates and aluminates are preferredactivators. It is anticipated that they will not be able to bind theneutral donor atoms of the polyhaptate ligand in a Lewis acid manner.

In a further embodiment, a polymerization process according to thepresent invention (invention polymerization process), such as thepolymerization or copolymerization of olefins, comprises the steps ofoptionally contacting the transition metal complex of the catalystsystem with an activator, optionally contacting the complex with ascavenger, and contacting the transition metal complex with suitablefeedstocks.

In a preferred embodiment, a polymerization process according to thepresent invention (invention polymerization process), such as thepolymerization or copolymerization of olefins, comprises the steps ofactivating (ionizing) the Group 3 or Lanthamide metal component to acation (the catalyst) and contacting it with suitable feedstocks.

Those skilled in the art will recognize that some forms of thetransition metal complex of the catalyst system will not require anactivator e.g. certain cationic compositions or neutral compositionsdirectly competent for polymerization of olefins. Additionally it willbe recognized that certain compositions of the transition metal complexof the catalyst system in low oxidation states (e.g. less than 3+) willbe capable of olefin polymerization upon contact with activators orscavengers. For example where L′ or Q are dienes which can be formallyconsidered neutral or dianionic ligands, those skilled in the art willunderstand that polymerization activity may be observed directly uponcontact with olefin or after treatment with activator and/or scavenger.Likewise where L′ is cyclooctene or cyclooctadiene, protonation of thebound olefin will result in the creation of a cationic metal-alkylcomplex which is formally two oxidation states higher than the precursorcomplex and may be competent for polymerization.

These feedstocks contain predominately one monomer forhomopolymerization; they contain monomer mixtures for copolymerization.Suitable feedstocks are made up of any desired mixture of ethylene,C₃–C₂₀ α-olefins, C₅–C₂₀ diolefins, acetylenically unsaturated monomers,or other unsaturated monomers. The catalyst can optionally be dissolved,suspended, or fluidized in a suitable liquid or gaseous polymerizationdiluent. The catalyst is activated with alumoxanes, modified alumoxanes,non-coordinating anion activators, Lewis acids or the like, (alone or incombination), with an aluminum-to-non-coordinating-anion orLewis-acid-to-transition-metal molar ratio of about 1:10 to about20,000:1 or more. The catalyst reacts with the monomer(s) from about−100° C. to about 300° C. for about one second to about 10 hours toproduce a polyolefin having from about 1000 or less to about 5,000,000or more weight average molecular weight and from about 1.5 to about 15or greater molecular weight distribution.

In another embodiment, the metal complex is represented by the followingformula:

M is a metal in a +3 oxidation state.

LTE is a multidentate ligand; Q are independently monoanionic ligandsselected from halide, hydride, hydrocarbyl, alkoxide, aryloxide, amideor phosphide radicals. Both Q together may be an alkylidene or acyclometallated hydrocarbyl or any other divalent anionic chelatingligand, or a diene, but may not be a substituted or unsubstitutedcyclopentadienyl radical.

L is a bulky, neutral multidentate ligand containing at least two,preferably three, Group-15 or -16 atoms. In a preferred embodiment,these atoms are nitrogen. The geometry of L is such that it coordinatesto the metal through the Group-15 atoms' lone pair electrons. Ligandgeometry orients the lone pair electrons so that they overlap themetal's frontier d-orbitals, reminiscent of η⁵, cyclopentadienyl side-oncoordination.

T is an optional covalent bridging group containing at least one Group13–16 atom. When present, it connects the multidentate ligand, L, withthe anionic ligand, E, and completes a metallocycle fragment, M(LTE).T's chain length influences the geometry of the metallocycle fragment.Examples of T include, but are not limited to, dialkyl, alkylaryl ordiaryl, silicon or germanium radicals, alkyl or aryl, phosphine or amineradicals, or hydrocarbyl radicals such as methylene, ethylene, andisopropylene.

E is an anionic ligand containing at least one group 14–16 element andmay be a substituted or unsubstituted, cyclopentadienyl, Group-15 ligandsuch as nitrogen or phosphorus, or Group-16 element such as oxygen orsulfur.

When E is a substituted cyclopentadienyl ligand, the substitution canoccur on the ring, keeping the C₅ ring intact (on-ring substitution), orcan occur in the ring, creating heterocyclic compounds (in-ringsubstitution). On-ring substitutions range from simple unitarysubstitution up to the replacement of multiple hydrogen atoms withmultidentate ligands forming fused-ring systems such as in- or on-ringsubstituted, or unsubstituted, fluorenyl or indenyl ligands. Animportant characteristic of a cyclopentadienyl ligand is that the5-member, substantially planar ring be preserved (heterocyclic orhomocyclic), including the π-electrons used to coordinate, side on, toM.

L′ is a neutral Lewis base such as, diethyl ether, tetrahydrofuran,dimethylaniline, trimethylphosphine, lithium chloride or the like, andoptionally covalently binds to one or both X. L′ can also be a secondtransition metal of the same type, i.e. the transition metal componentcan be dimeric if both of the transition metals are the same orbimetallic if they are different.

In cationic form as activated for olefin polymerization, the transitionmetal complex is believed to have the following formula:

M, T, E, L, Q and L′ are as defined above and NCA is a weaklycoordinating or noncoordinating anion that balances the cationiccomplex's charge.

In yet another embodiment, the transition metal component of thecatalyst system has the formula:

M, T, E, L, Q and C′ are as defined above.

Alternatively, as in structure D, E is JR′_(z). J is a Group 15 or 16element; z is 2 when J is a Group 15 element and 1 when J is a Group 16element. R, R′ and R″ are defined below.

In yet another embodiment, the multidentate ligand is joined to themonoanionic ligand through a substituted phenol joined forming anall-carbon bridge to the multidentate neutral portion of the ligand.

The structures shown below represent examples of ligand and/or catalystprecursor that are within the scope of this invention. This list doesnot define the full scope of the invention but rather is exemplary only.

The metal complexes according to this invention can be prepared byvarious conventional routes.

The metal complexes (catalyst precursors) according to the invention aresuitable for polymerization when activated by methods known in themetallocene art. Suitable activators typically include alumoxanecompounds, modified alumoxane compounds, and ionizing anion precursorcompounds that abstract one reactive, σ-bound metal ligand making themetal complex cationic and providing a charge-balancing noncoordinatingor weakly coordinating anion.

Alkylalumoxanes and modified alkylalumoxanes are suitable as catalystactivators, particularly when the abstractable ligand is a halide.Alumoxane components useful as a catalyst activator are typicallyoligomeric aluminum compounds represented by the general formula(R²—Al—O)_(m), (cyclic) or R³(R⁴—Al—O)_(m)AlR⁵ (linear), although otherstructural variations may exist. In a general alumoxane formula, eachR²—R⁵ is independently a C₁ to C₂₀ hydrocarbyl radical, for example,methyl, ethyl, and isomers of propyl, butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, heptadecyl, octadecyl, nonadecyl or icosyl, and m is aninteger from 1 to about 50. Most preferably, R²—R⁵ is methyl and m is atleast 4. If an alkyl aluminum halide is used in the alumoxanepreparation, R²—R⁵ can also be halides. Alumoxanes can be prepared byvarious procedures known in the art. For example, an aluminum alkyl maybe treated with water dissolved in an inert organic solvent, or it maybe contacted with a hydrated salt, such as hydrated copper sulfatesuspended in an inert organic solvent, to yield an alumoxane. Generally,however prepared, the reaction of an aluminum alkyl with a limitedamount of water yields a linear and cyclic alumoxane mixture. Modifiedand unmodified methylalumoxanes are preferred. Mixtures of differentalumoxanes and modified alumoxanes may also be used. For furtherdescriptions, see U.S. Pat. Nos. 4,665,208, 4,952,540, 5,041,584,5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463,4,968,827, 5,329,032, 5,248,801, 5,235,081, 5,157,137, 5,103,031 and EP0 561 476 A1, EP 0279586B1, EP 0516476A, EP 0594218A1 and WO 94/10180.

When the activator is an alumoxane, the minimummetal-complex-to-activator molar ratio is equal to about 1:5000,preferably about 1:500 and most preferably about 1:100. The maximummetal complex to activator molar ratio is about 1:1 and most preferablyabout 1:10.

The term “noncoordinating anion” is recognized to mean an anion, asrepresented by the symbol NCA above, which either does not coordinate tothe metal cation or that does coordinate to the metal cation, but onlyweakly enough that a neutral Lewis base, such as an olefinically oracetylenically unsaturated monomer can displace it.

Descriptions of ionic catalysts with a transition-metal cationic complexand a noncoordinating anion, suitable for polymerization appear in U.S.Pat. Nos. 5,064,802, 5,132,380, 5,198,401, 5,278,119, 5,321,106,5,347,024, 5,408,017, 5,599,671, and WO 92/00333 and WO 93/14132. Theseteach a preferred preparation method in which metallocenes areprotonated by noncoordinating anion precursors such that an alkyl orhydride group is abstracted from the transition metal compound making itboth cationic and charge-balanced by the noncoordinating anion. Sincesimilar ligands may be present in this invention's metal compounds,similar polymerization catalyst activation methods may be followed.Benzyl is a preferred abstractable hydrocarbyl radical.

Using ionic compounds lacking an active proton, but capable of producingboth an active metal cationic complex and a noncoordinating anion, isalso possible. See, EP-A-0 426 637, EP-A-0 573 403 and U.S. Pat. No.5,387,568 for illustrative ionic compounds. Reactive cations of theionic compounds, other than the Bronsted acids, include ferrocenium,silver, tropylium, triphenylcarbenium and triethylsilylium, and alkaliand alkaline earth metal cations such as sodium, magnesium or lithiumcations. A further class of suitable noncoordinating anion precursorsare hydrated salts comprising alkali or alkaline-earth metal cations anda non-coordinating anion as described above. The hydrated salts are madeby reacting the metal-cation-noncoordinating-anion salt with water, forexample, by hydrolysis of the commercially available or readilysynthesized [Li]⁺[B(pfp)₄]⁻, which yields [Li(H₂O)_(x)]⁺[B(pfp)₄]⁻: pfpis pentafluorophenyl or perfluorophenyl.

Any metal or metalloid that can form a compatible, weakly or negligiblycoordinating complex may be used or contained in the noncoordinatinganion. Suitable metals include, but are not limited to, aluminum, goldand platinum. Suitable metalloids include, but are not limited to,boron, phosphorus and silicon. The description of noncoordinating anionsand their precursors in the documents cited in the paragraphs above areincorporated by reference for purposes of U.S. patent practice.

An additional method of making this invention's active polymerizationcatalysts uses ionizing-anion precursors that are initially neutralLewis acids but form a cationic metal complex and a noncoordinatinganion, or a Zwitterionic complex upon reaction with the inventioncompounds. For example, tris(pentafluorophenyl) boron or aluminum act toabstract a hydrocarbyl or hydride ligand to yield an invention cationicmetal complex and stabilizing noncoordinating anion, see EP-A-0 427 697and EP-A-0 520 732 for illustrations of analogous Group-4 metallocenecompounds. Also, see the methods and compounds of EP-A-0 495 375. Forformation of Zwitterionic complexes using analogous Group 4 compoundssee U.S. Pat. Nos. 5,624,878; 5,486,632; and 5,527,929. The descriptionof noncoordinating anions and their precursors in these documents areincorporated by reference for purposes of U.S. Patent practice.

When the cations of noncoordinating anion precursors are Bronsted acidssuch as protons or protonated Lewis bases (excluding water), orreducible Lewis acids such as ferrocenium or silver cations, or alkalior alkaline earth metal cations such as those of sodium, magnesium orlithium, the transition-metal-to-activator molar ratio may be any ratio.While the molar ratio may take any value, the minimum is preferablyabout 1:10, more preferably about 1:5, even more preferably about 1:12.The maximum transition-metal-to-activator molar ratio is preferablyabout 10:1, more preferably about 5:1, even more preferably about 1.2:1.The most preferred, transition-metal-to-activator molar ratio is 1:1.Combinations of the described activator compounds may also be used foractivation. For example, tris(perfluorophenyl) boron can be used inconjunction with methylalumoxane.

The invention's catalyst complexes are useful in polymerizingunsaturated monomers conventionally known to undergometallocene-catalyzed, coordination polymerization such as solutionpolymerization, slurry polymerization, gas-phase polymerization, andhigh-pressure polymerization. These catalysts may be supported and assuch will be particularly useful in the known, fixed-bed, moving-bed,fluid-bed, slurry, or solution operating modes conducted in single,series, or parallel reactors.

Generally, when using this invention's catalysts, particularly when theyare immobilized on a support, the complete catalyst system willadditionally comprise one or more scavenging compounds. Here, the term“scavenging compounds” means compounds that remove polar impurities fromthe reaction environment. Impurities can be inadvertently introducedwith any of the polymerization reaction components, particularly withthe solvent, monomer and catalyst feeds.

These impurities adversely affect catalyst activity and stability. Theydiminish or eliminate catalytic activity, particularly when ionizinganion precursors activate the catalyst system. Polar impurities, orcatalyst poisons include water, oxygen, metal impurities, etc.Preferably, purifying steps occur before introducing reaction componentsto the reaction vessel. Such steps include chemical treatment or carefulseparation during or after the various components' synthesis orpreparation. But such steps will rarely allow polymerization withoutusing some scavenging compounds. Normally, the polymerization processwill still use at least small amounts of scavenging compounds.

Typically, the scavenging compound will be an organometallic compoundsuch as the Group-13 organometallic compounds of U.S. Pat. Nos.5,153,157, 5,241,025 and WO-A-91/09882, WO-A-94/03506, WO-A-93/14132,and that of WO 95/07941. Exemplary compounds include triethyl aluminum,triethyl borane, triisobutyl aluminum, methylalumoxane, isobutylaluminumoxane, and tri-n-octyl aluminum. Those scavenging compoundshaving bulky or C₆–C₂₀ linear hydrocarbyl substituents covalently boundto the metal or metalloid center are preferred to minimize adverseinteraction with the active catalyst. Examples include triethylaluminum,but more preferably, bulky compounds such as triisobutylaluminum,triisoprenylaluminum, and long-chain linear alkyl-substituted aluminumcompounds, such as tri-n-hexylaluminum, tri-n-octylaluminum, ortri-n-dodecylaluminum. When alumoxane is used as the activator, anyexcess over that needed for activation will scavenge impurities andadditional scavenging compounds may be unnecessary. Alumoxanes also maybe added in scavenging quantities with other activators, e.g.,methylalumoxane, [Me₂HNPh]⁺[B(pfp)₄]⁻ or B(pfp)₃. In this invention,only enough scavenging agent is used to enhance activity: pure enoughfeeds avoid scavenging agent altogether.

The invention catalysts can be supported for gas-phase, bulk, or slurrypolymerization use, or otherwise as needed. Numerous support methods areknown for catalysts in the olefin copolymerization art, particularlyalumoxane-activated catalysts; any are suitable for this invention'sbroadest practice. See, for example, U.S. Pat. Nos. 5,057,475 and5,227,440. An example of supported ionic catalysts appears in WO94/03056. U.S. Pat. No. 5,643,847 and WO 96/04319A describe aparticularly effective method. A bulk or slurry process using thisinvention's supported metal complexes activated with alumoxane can beused for ethylene-propylene rubber as described in U.S. Pat. Nos.5,001,205 and 5,229,478. Additionally, those processes suit thisinvention's catalyst systems. Both polymers and inorganic oxides mayserve as supports, as is known in the art. See U.S. Pat. Nos. 5,422,325,5,427,991, 5,498,582 and 5,466,649, and international publications WO93/11172 and WO 94/07928. All of these documents are incorporated byreference for purposes of U.S. patent practice.

Preferred embodiments employ the catalyst system in the liquid phase(solution, slurry, suspension, bulk phase, or suitable combinations), inhigh-pressure, liquid or supercritical fluid phases, or in the gasphase. Each may be employed in singular, parallel, or series reactors.The liquid processes comprise contacting olefin monomers with thecatalyst system described above. The reaction is carried out in asuitable diluent or solvent for a time sufficient to produce thisinvention's copolymers. Both aliphatic and aromatic hydrocarbyl solventsare suitable; hexane and toluene are preferred. Typically, in bulk andslurry processes, the liquid monomer slurry contacts the supportedcatalysts. Gas-phase processes typically use a supported catalyst andare conducted in any suitable manner for ethylene homo- orcopolymerization. Illustrative examples may be found in U.S. Pat. Nos.4,543,399, 4,588,790, 5,028,670, 5,382,638, 5352,749, 5,436,304,5,453,471, and 5,463,999, and WO 95/07942. Each is incorporated byreference for purposes of U.S. patent practice.

Polymerization reaction temperatures can vary. The minimum reactiontemperature is about −50° C.; preferably the minimum is about −20° C.The maximum temperature is about 250° C. preferably at or below about220° C. Most preferably, the reaction temperature will be at or belowabout 200° C.

Linear polyethylene, including high- and ultra-high-molecular-weightpolyethylenes are produced by adding ethylene, and optionally one ormore other monomers, to a reaction vessel with an invention catalyst.The polymers can include both homopolymers and copolymers with otherα-olefin, α-olefinic diolefin, or non-conjugated diolefin monomers, forexample C₃–C₂₀ olefins, C₄–C₂₀ diolefins, C₄–C₂₀ cyclic olefins, orC₈–C₂₀ styrenic olefins. The invention catalyst is first slurried withor dissolved in a solvent, such as hexane or toluene. Most often,cooling removes polymerization heat. Gas-phase polymerization can beconducted, for example, in a continuous, fluidized-bed, gas-phasereactor operated between about 200–3000 kPa and at about 60–160° C.,using hydrogen as a reaction modifier (100–200 ppm), a C₄–C₈ comonomerfeedstream (0.5–12 mol %), and a C₂ feedstream (25–35 mol %). See, U.S.Pat. Nos. 4,543,399; 4,588,790; 5,028,670; 5,405,922; and 5,462,999,which are incorporated by reference for purposes of U.S. patentpractice.

Ethylene-α-olefin (including ethylene-cyclic olefin andethylene-α-olefin-diolefin) elastomers of high molecular weight and lowcrystallinity can be prepared using the invention catalysts undertraditional solution polymerization conditions or by introducingethylene gas into a slurry of polymerization diluent and catalyst. Thepolymerization diluent contains α-olefin monomers, cyclic olefinmonomers, or their mixtures with other polymerizable andnon-polymerizable monomers. In this case, polymerization reactionpressure varies, as well. The minimum pressure is about 0.0013 bar; apressure of at least about 0.1 bar is more preferred. Most preferably,the reaction pressure is at least about 1.0 bar. The maximum pressure isabout 2500 bar, with a pressure at most about 1600 bar being preferred.The most preferred maximum pressure is about 500 bar. Typical ethylenepressures will be between 10 and 1000 psig (69–6895 kPa) and thepolymerization diluent temperature will typically be between −10 and160° C. The process can use a stirred-tank reactor, or more than onereactor operated in series or parallel. See the general disclosure ofU.S. Pat. No. 5,001,205, which is incorporated by reference for itsdescription of polymerization processes, ionic activators and usefulscavenging compounds.

Slurry or gas-phase reaction processes can use pre-polymerization of thesupported invention catalyst to further control polymer particlemorphology, as is known in the art. For example, such reaction can beaccomplished by prepolymerizing a C₂–C₆ α-olefin for a limited time.Ethylene contacts the supported catalyst at between −15° to 30° C. andethylene pressure of up to about 250 psig (1724 kPa) for 75 min toobtain a polyethylene coating on the support (30,000–150,000 molecularweight). The above polymerization process can then use thepre-polymerized catalyst. Additionally, polymeric resins may be used asa support coating, typically by suspending a support in dissolvedpolystyrene resin or similar material followed by separation and drying.

Other olefinically unsaturated monomers besides those specificallydescribed above may be polymerized using the invention catalysts, forexample, styrene, alkyl-substituted styrene, ethylidene norbornene,norbornadiene, dicyclopentadiene, vinylcyclohexane, vinylcyclohexene,and other olefinically-unsaturated monomers, including other cyclicolefins, such as cyclopentene, norbornene, and alkyl-substitutednorbornenes. Copolymerization can also incorporate α-olefinicmacromonomers of up to 1000 or more mer units.

The invention catalyst compositions can be used individually asdescribed above or can be mixed with other known polymerizationcatalysts to prepare polymer blends. Monomer and catalyst selectionallows polymer blend preparation under conditions analogous to thoseusing individual catalysts. Polymers having increased MWD for improvedprocessing and other traditional benefits available from polymers madewith mixed catalyst systems can thus be achieved.

EXAMPLES

The following examples are presented to illustrate the discussion above.Although the examples may be directed toward certain embodiments of thepresent invention, they do not limit the invention in any specific way.In these examples, certain abbreviations are used to facilitate thedescription. These include standard chemical abbreviations for theelements and certain commonly accepted abbreviations, such as:Me=methyl, Et=ethyl, Bu=butyl, Ph=phenyl, MAO=methylalumoxane, andTHF=tetrahydrofuran.

All parts, proportions, and percentages are by weights unless otherwiseindicated. All molecular weights are weight average molecular weightunless otherwise noted. Molecular weights (weight average molecularweight (Mw) and number average molecular weight (Mn)) were measured byGel Permeation Chromatography, unless otherwise noted, using a Waters150 Gel Permeation Chromatograph equipped with a differential refractiveindex detector and calibrated using polystyrene standards. Samples wererun in either THF (45° C.) or in 1,2,4-trichlorobenzene (145° C.),depending upon the sample's solubility, using three Shodex GPC AT-80 M/Scolumns in series. This general technique is discussed in “LiquidChromatography of Polymers and Related Materials III” J. Cazes Ed.,Marcel Decker, 1981, page 207, which is incorporated by reference forpurposes of U.S. patent practice. No column spreading corrections wereemployed but data on generally accepted standards, e.g. National Bureauof Standards Polyethylene 1475, demonstrated a precision with 0.1 unitsfor M_(w)/M_(n), which was calculated from elution times. Numericalanalyses were performed using Expert Ease® software available fromWaters Corporation. The term “psid” refers to the differential pressureresulting from monomer addition.

All preparations were performed under an inert nitrogen atmosphere,using standard Schlenk or glovebox techniques, unless mentionedotherwise. Dry solvents were purchased from Aldrich in anhydrous,air-free form and were degassed and vacuum transferred fromsodium/benzophenone (THF, diethyl ether) phosphorus pentoxide (methylenechloride) or CaH₂ (pentane) before use. If these additional steps werenot taken some compounds were observed to form insoluble light ppt.supon handling in solution. The toluene used in the polymerizationexperiments (high purity from ExxonMobil Chemical Co.) was passedthrough columns of supported reduced copper scavenger and molecularsieves (Oxyclear) and activated alumina (basic, Brockmann 1). Ethylene(high purity from ExxonMobil Chemical Co.) was likewise purified. Hexeneobtained anhydrous and air-free was further sparged with nitrogen.Deuterated solvents were degassed and vacuum transferred fromsodium/benzophenone (THF) or CaH₂ (benzene, toluene, C₆D₅Br, methylenechloride) before use. ScCl₃ was purchased from Aldrich and YCl₃ fromStrem, while Y(CH₂SiMe₃)₃(THF)_(n) (n˜2.3) was prepared according to themethod of Lappert and Pearce (J. C. S. Chem. Comm. (1973) 126). Theligands R₂tacn-6-CH₂—Ar-1-OH (L² R=Me, Ar=2,4-^(t)Bu₂; L³ R=^(i)Pr,Ar=2,4-Me₂) were purchased from an outside supplier and can be madeaccording to the method of Tolman et al. (J. Am. Chem. Soc., 119 (1997)8217). Triethylhexahydrotriazine, Et₃htz(1,3,5-triethyl-[1,3,5]triazacyclohexane), was purchased from Aldrich(drid over CaH₂ and filtered). The parent triazacyclononane,triaza[1,4,7]cyclononane was purchased from Aldrich or Macrocyclics. Thetrimethyl derivative 1,4,7-trimethyl-triaza[1,4,7]cyclononane was madeby treating the parent macrocycle with formaldehyde in formic acid asdescribed by Wiegahardt et al. (Inorg. Chem., 21 (1982) 3086). Thepotassium salt of 2,6-diisopropylphenol (2,6-^(I)Pr₂C₆H₃OK) was made bytreating the phenol with excess KH in THF.

Example Ligand 1

Synthesis of L²K (Me₂tacn-6-CH₂-2,4-^(t)Bu₂-C₆H₃-1-OK).

To 0.208 g Me₂tacn-6-CH₂-2,4-^(t)Bu₂-C₆H₃-1-OH in 25 mL of THF wasslowly added 0.029 g of KH causing gas evolution. About 0.060 g more KHwas likewise added. After stirring over night the orange-brown solutionwas filtered via Celite, washed with THF and the solvent removed undervacuum. The residue was stirred with pentane which was stripped.Attempted recrystallization at −35 C yielded ppt.s but not crystals sothe solvent was stripped affording 0.177 g (77% yield) of orange-brownmaterial which was determined to be the desired product by ¹H-NMRanalysis.

Example Catalyst 1

Synthesis of L²ScCl₂ ((Me₂tacn-6-CH₂-2,4-^(t)Bu₂-C₆H₃-1-O)ScCl₂).

ScCl₃, 0.066 g, was added to 50 mL refluxing THF, refluxed about 25 min,and removed from the heat. The entire sample of L²K from the previousexample that had been taken up in about 1 mL of THF-d₈ was diluted withabout 20 mL of THF and slowly added dropwise to the ScCl₃ solution withstirring. The next day an aliquot was removed for ¹H-NMR analysis andthe remainder stripped under vacuum. The residue was extracted withmethylene chloride, filtered on a medium frit to remove red-brownsolids, and the filtrate stripped to dryness to yield 0.142 g (70%yield) of light solids whose ¹H-NMR was consistent with the desiredstructure.

Example Catalyst 2

Synthesis of Me₃tacn(ArO)ScCl₂ (Ar=2,6-^(I)Pr₂Ph).

ScCl₃, 0.350 g, was added to 50 mL refluxing THF, refluxed about 25 min,and removed from the heat. After cooling, 0.410 g of Me₃tacn was addedfollowed by 0.502 g of solid 2,6-^(I)Pr₂PhOK causing a transientlavender coloration. After stirring overnight white flocculentprecipitates were observed. The solvent was removed under vacuum and thesolids were triturated with methylene chloride which was removed undervacuum. The solids were triturated unintentionally with THF which wasremoved under vacuum and the methylene chloride trituration repeated.The residues were then extracted into methylene chloride and the mixturefiltered on a medium porosity frit, washed with methylene chloride, andthe filtrate reduced to dryness under vacuum to yield 0.784 g of ayellow-white powder (73% yield) whose ¹H-NMR was consistent with thedesired structure.

Example Catalyst 3

Synthesis Et₃htz(ArO)ScCl₂ (Ar=2,6-^(I)Pr₂Ph).

ScCl₃, 0.350 g, was added to 50 mL refluxing THF, refluxed about 25 min,and removed from the heat. After cooling, 0.412 g of Et₃htz(triethylhexahydrotriazine) was added followed by 0.509 g of solid2,6-^(I)Pr₂PhOK. After stirring the solution appeared milky. The solventwas removed under vacuum and the solids were triturated with methylenechloride which was removed under vacuum. The residues were thenextracted into methylene chloride and the mixture filtered on a mediumporosity frit, washed with methylene chloride, and the filtrate reducedto dryness under vacuum to yield 0.780 g of a white powder (73% yield)whose 1H-NMR was consistent with the desired structure.

Example Catalyst 4

Synthesis of L¹Y(CH₂SiMe₃)₂ ((^(i)Pr₂tacn-6-CH₂-2,4-^(t)Bu₂-C₆H₃-1-O)Y(CH₂SiMe₃)₂).

A −35 C solution of 0.204 g L¹H in 5–10 mL of toluene was addeddrop-wise into a −35 C solution of 0.239 g Y(CH₂SiMe₃)₃(THF)₂₃ in 5–10mL of toluene. After warming 2 hr the solvent was removed under vacuum.The solids were triturated with several mL of pentane and cooled to −35C. The precipitates were collected by filtration and dried under vacuumaffording 0.223 g white solids (69% yield) whose ¹H-NMR was consistentwith the desired structure.

Example Polymerization 1

Vial Polymerization with L²ScCl₂.

In a vial polymerization test, a 20 mL vial was filled with 0.002 g of(##), 10 mL toluene, 1.58 g 30 wt % Albemarle MAO, and a stir bar. Aseptum was fitted on the top and 1 atm ethylene purged through theheadspace. After stirring, solids appeared. After 45 minutes, thesolution was quenched with methanol and then stirred with 25 mL 1 N HCl,then 12 mL 4 N HCl to dissolve the aluminum oxides. The sample wasfiltered, washed with water and dried under vacuum at 80° C. overnight.The amount collected from the filter paper was 0.007 g.

Example Polymerization 2

Autoclave Polymerization with EXAMPLE CATALYST 1 (L²ScCl₂)

A 2 L Zipperclave reactor was charged with 800 mL toluene and 1 mL of 10wt. % Albemarle MAO and warmed to 60° C. Next, 0.0050 g of 1 was weighedout and treated with 2 mL of 10 wt. % Albemarle MAO with stirring. Thissolution was injected into the reactor which was then pressurized with75 psid of ethylene and stirred at 800–1000 rpm. After 60 minutes, thereactor was opened, the material poured into isopropanol, treated withacidified methanol, and the solvent weathered off under a stream of air.This material was stirred with fresh acidifed methanol, filtered, washedwith water, and dried under vacuum at 80° C. overnight to yield 0.306 gof white polyethylene.

Example Polymerizations 3

These polymerizations were performed according to the procedure ofExample Polymerization 2, and the materials and amounts that weredifferent are recorded in Table 1. Blank runs in which either notransition metal complex or no methylalumoxane were added to the reactorwere performed and indicated the necessity of having both componentspresent for significant polymerization activity.

TABLE 1 MAO Polymerization Data MAO wi. MAO in. Cat. catalyst reactorHexene Run t Yield Specific Activity Ex. Catalyst mmols mmols mmols AI/MmL min g gPE/mmol M atm hr 2 L₂ScCl₂ 0.01081 3.06467 1.53234 425.1 0 600.306 5.547 3C none 0.00000 NA 4.59701 NA 0 30 0.036 §0.003 4 L₂ScCl₂0.01081 3.06467 1.53234 425.1 90 30 0.210 7.613 5 L₂ScCl₂ 0.010813.06467 1.53234 425.1 90 60 0.600 10.876 6 Et₃htzDIPScCl₂ 0.010773.06467 1.53234 427.0 0 60 0.890 16.202 7C none 0.00000 NA 4.59701 NA 030 0.049 §0.004 8C L₂ScCl₂* 0.01081 0.00000 0.00000 0.0 0 30 0.000 0.0009 Et₃htzDIPScCl₂ 0.01077 3.06467 1.53234 427.0 90 60′ 0.710 12.925 *Thiscomparative run contained 0.050 mL of 25 wt% TEAL in heptane (Akzo) asscavenger. §Here the mmoles Al are used for mmoles M.

Example Polymerization 9

Autoclave Polymerization with EXAMPLE CATALYST 4 (L¹Y(CH₂SiMe₃)₂)

Initial polymerization attempts under the conditions of examplepolymerization 2 except that 5 mg charges of Catalyst 4 in 5 mL tolueneadded into a reactor containing 2 mL 10 wt. % MAO yielded about 0.2 g orless of polymer. Similarly, adding 5 mL of a solution made from 6 mgCatalyst 4 and 7 mg dimethylanilinium tetrakispentafluorophenylborate in12 mL toluene, into a reactor with 0.050 mL triisobutyl aluminum (25 wt.% in toluene) yielded negligible amounts of polymer. We believe thesubstitution of a smaller alkyl group on yttrium would improvepolymerization performance.

1. An olefin polymerization process comprising: (a) providing monomer;(b) providing a polymerization catalyst comprising: (i) a Group -7, -8or -9 metal in a +3 oxidation state; (ii) a multidentate ligandcomprising: (iii) a subpart comprising at least three Group-15 moieties,each bridged to another through at least one Group-14 moiety wherein thesubpart connects to the metal and wherein each Group-15 moiety isoptionally bonded to a substituted or unsubstituted organic group; (iv)a monoanion connected to the metal, wherein the monoanion is other thancyclopentadienyl; and (v) a bridge that connects the monoanion to thesubpart; (c) contacting the monomer with the catalyst under suitablepolymerization conditions.
 2. The process of claim 1 wherein the subpartcontains a ring comprising at least two of the Group-15 moieties.
 3. Theprocess of claim 1 wherein the multidentate ligand contains a ringcomprising at least three Group-15 moieties.
 4. The process of claim 1wherein the bridge comprises at least one Group-13-to-16 element.
 5. Anolefin polymerization process comprising: (a) providing monomer; (b)providing a polymerization catalyst precursor comprising: (i) a Group-7, -8 or -9 metal in a +3 oxidation state; (ii) a multidentate ligandcomprising: (A). a subpart comprising at least three Group-15 moieties,each bridged to another through at least one Group-14 moiety wherein thesubpart connects to the metal and wherein each Group-15 moiety isoptionally bonded to a substituted or unsubstituted organic group; (B) amonoanion connected to the metal, wherein the monoanion other thancyclopentadienyl; and (C) a bridge that connects the monoanion to thesubpart; (c) providing an activator, (d) activating the catalystprecursor with the activator, end (e) contacting the monomer with theactivated catalyst under suitable polymerization conditions.
 6. Acatalyst comprising an activator and a metal complex wherein the metalcomplex has the following formula(C₆H₁₂N₃R₂TNR′)MX₂L′ wherein (a) M is a +3 oxidation state Group-4 to -9metal; (b) X are abstractable ligands (c) R is selected from (i) C₁–C₂₀hydrocarbyl radicals; (ii) C₁–C₂₀—substituted hydrocarbyl radicalshaving at least one hydrogen group wherein one of the at least onehydrogen groups is substituted by a halogen; amido; phosphido; alkoxy;or aryloxy group; and (iii) C₁–C₂₀ hydrocarbyl-substituted Group-13–14metalloid radicals; (d) T is a covalent bridging group comprising atleast one Group-14 or -15 atom; (e) R′ is selected from (iv) Halide; (v)C₁–C₂₀ hydrocarbyl radicals; (vi) C₁–C₂₀—substituted hydrocarbylradicals having at least one hydrogen group wherein one of the at leastone hydrogen groups is substituted by a halogen; amido; phosphido;alkoxy; or aryloxy group; and (vii) C₁–C₂₀ hydrocarbyl-substitutedGroup-13–14 metalloid radicals; (f) L′ is a neutral Lewis base.
 7. Acatalyst comprising an activator and a metal complex with the followingformula(C₆H₁₂N₃R₂TCp)MX₂L′ wherein (a) M is a +3 oxidation state Group-4 to -9metal; (b) X are abstractable ligands; (c) each R are independentlyselected from (i) C₁–C₂₀ hydrocarbyl radicals; (ii) C₁–C₂₀—substitutedhydrocarbyl radicals having at least one hydrogen group wherein one ofthe at least one hydrogen groups is substituted by a halogen; amido;phosphido; alkoxy or aryloxy group; and (iii) C₁–C₂₀hydrocarbyl-substituted Group-13–14 metalloid radicals; (d) T is acovalent bridging group comprising at least one Group-14 or -15 atom;(e) L′ is a neutral Lewis base; and (f) Cp is a cyclopentadienyl ligand.